Question 40 of 69intermediate🔧 ApplyShort Answer2 marks

Classify the following species into Lewis acids and Lewis bases and show how these act as Lewis acid/base: (a) OH−OH^- (b) F−F^- (c) H+H^+ (d) BCl3BCl_3.

(a)
Answer

OH−OH^- is a Lewis base as it can donate an electron lone pair (:OH−:OH^-).

(b)
Answer

F−F^- acts as a Lewis base as it can donate any one of its four electron lone pairs.

(c)
Answer

H+H^+ is a Lewis acid as it can accept a lone pair of electrons from bases like hydroxyl ion and fluoride ion.

(d)
Answer

BCl3BCl_3 acts as a Lewis acid as it can accept a lone pair of electrons from species like ammonia or amine molecules.

Explanation

According to the Lewis concept, an acid is a species which accepts an electron pair and a base is a species which donates an electron pair. Hydroxyl and fluoride ions possess lone pairs of electrons that they can donate, classifying them as Lewis bases. Conversely, a proton (H+H^+) and BCl3BCl_3 are electron-deficient species that can accept lone pairs from other molecules, classifying them as Lewis acids.

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